<template>
    <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
    <el-step title="填写课程基本信息"/>
    <el-step title="创建课程大纲"/>
    <el-step title="最终发布"/>
    </el-steps>

    <!-- Todo -->
    <el-form label-width="120px">

        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
        <el-form-item label="课程分类">
            <el-select
                v-model="courseInfo.subjectParentId" 
                placeholder="一级分类" @change="subjectLevelOneChanged">

                <el-option
                    v-for="subject in subjectOneList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>

            </el-select>

            <!-- 二级分类 -->
            <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                <el-option
                    v-for="subject in subjectTwoList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>
            </el-select>
        </el-form-item>
 
        <!-- 课程讲师 TODO -->
        <!-- 课程讲师 -->
        <el-form-item label="课程讲师">
        <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">

            <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>

        </el-select>
        </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介 TODO -->
        <!-- 富文本标签 -->
        <el-form-item label="课程简介">
            <el-input v-model="courseInfo.description" placeholder=" "/>
        </el-form-item>
     
         <!-- 课程封面 TODO -->
        <!-- 课程封面-->
        <el-form-item label="课程封面">

        <el-upload
            :show-file-list="false"
            :on-success="handleAvatarSuccess"
            :before-upload="beforeAvatarUpload"
            :action="BASE_API+'/eduoss/fileoss'"
            class="avatar-uploader">
            <img :src="courseInfo.cover"  width="50px" height="50px">
        </el-upload>

        </el-form-item>

         <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>


    <el-form-item>
    <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保
    存并下一步</el-button>
    </el-form-item>
    </el-form>
    </div>
</template>

<script>
// 引入js
import subject from '@/api/edu/subject'
import course  from '@/api/edu/course'
export default {
   
    data(){
        return{
          saveBtnDisabled:false,
          courseInfo:{
                title: '',
                subjectId: '',//二级分类id
                subjectParentId:'',//一级分类id
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/01.jpg',
                price: 0
          },
          courseId:'',//保存路径id
          BASE_API: process.env.BASE_API, // 接口API地址
            teacherList:[],//封装所有的讲师
            subjectOneList:[],//一级分类
            subjectTwoList:[]//二级分类
            
        }
    },
    created(){ 

       //路由携带params参数跳转
       if(this.$route.params&&this.$route.params.id)
       {
        this.courseId=this.$route.params.id
        //根据id查询课程方法
        this.getCourseInfo()
       }
       else{
        //初始化所有讲师
        this.getAllTeacher()
        //初始化一级分类
        this.getOneList();
       }
      
    },
    methods:{
       
        //根据id查询课程信息，进行信息回显
        getCourseInfo(){
            course.getCourseInfo(this.courseId).then(
                response=>{
                //数据回显
                   this.courseInfo=response.data.courseInfo
                   //查询一级分类,二级分类，前端需要的就是拿到数据，框架会进行展示
                   subject.getAllSubject().then(
                    response=>{
                        this.subjectOneList=response.data.list
                        //遍历一级分类，得到二级分类
                        for(var i=0;i<this.subjectOneList.length;i++)
                        {
                            if(this.courseInfo.subjectParentId===this.subjectOneList[i].id)
                            {
                                this.subjectTwoList=this.subjectOneList[i].children
                            }
                        }
                    }
                   )
                   //初始化所有的讲师
                   this.getAllTeacher()

                }
            )
        },

        //课程相关
        //二级联动 查询一次数据库,一级分类查出来之后，点击一级，再查询二级
        subjectLevelOneChanged(value){
             //value就是一级分类id值
            //遍历所有的分类，包含一级和二级
            console.log(value)
           for(let i=0;i<this.subjectOneList.length;i++)
           {
                var oneSubject=this.subjectOneList[i]
                if(oneSubject.id===value)
                {
                    //从一级分类获取里面所有的二级分类
                    this.subjectTwoList = oneSubject.children
                    //把二级分类id值清空
                    this.courseInfo.subjectId = ''
                }
           }
        },

        //查询一级分类
        getOneList(){
            subject.getAllSubject().then(response=>{
                this.subjectOneList=response.data.list;
            })

        },

        //得到所有的讲师
        getAllTeacher()
        {
            course.getAllTeachers().then(
                response=>{
                    // 后端返回 "items" list                   
                    this.teacherList=response.data.items;
                }
            ).catch(error=>{
             console.log(error)
         }) 
        } ,

        //上传封面之后
        handleAvatarSuccess(res,file){
            this.courseInfo.cover = res.data.url
        },
         //上传封面之前，规定图片大小和格式
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        saveOrUpdate(){
           //如果课程id存在则是修改，如果是不存在，则是添加
        
           //不存在id
           if(!this.courseInfo.id)
           {
                this.saveCourse()
           }
           //存在id
           else{
              this.updateCourse()
           }   
        },
        saveCourse(){
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '添加课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+response.data.courseId})
                })
        },
        updateCourse(){
            course.updateCourseInfo(this.courseInfo).then(
                response=>{
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });

                      //跳转到第二步
                      this.$router.push({path:'/course/chapter/'+this.courseId})

                }
            )
        }
    
    }
      
 }


</script>

<style scoped>
.tinymce-container {
line-height: 29px;
}

</style>